#app {
    font-family: Avenir, Helvetica, Arial, sans-serif;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-align: center;
    color: #2c3e50;
  }

body {
    margin: 0;
    padding: 0;
    font-family: "微软雅黑";
    font-size: 12px;
    color: #666;
}
  
 #nav{
     text-align: center;

 }
  
  #nav a {
    font-weight: bold;
  }
  
 a{
     text-decoration: none;
 }